China has launched an antitrust probe into Alibaba Group and will summon the technology giant’s Ant Group affiliate to meet in the coming days, regulators said on Thursday, in the latest blow for Jack Ma’s e-commerce and financial technology empire.

The probe is part of an accelerating crackdown on monopolistic behaviour in China’s booming internet space and the latest setback for Ma, the 56-year-old former school teacher who founded Alibaba and became China’s most famous entrepreneur. It follows China’s dramatic suspension last month of Ant’s planned $37bn initial public offering, which had been on track to be the world’s largest, just two days before shares were due to begin trading in Shanghai and Hong Kong.

In a strongly worded editorial, the ruling Communist Party’s People’s Daily said that if “monopoly is tolerated, and companies are allowed to expand in a disorderly and barbarian manner, the industry won’t develop in a healthy, and sustainable way”. Shares in Alibaba fell nearly 9 percent in Hong Kong on Thursday morning.

Regulators have warned Alibaba about the so-called “choosing one from two” practice under which merchants are required to sign exclusive cooperation pacts preventing them from offering products on rival platforms.

The State Administration for Market Regulation (SAMR) said in a statement on Thursday that it has launched a probe into the practice. Financial regulators will also meet with Alibaba’s Ant Group fintech affiliate in the coming days, according to a separate statement by the People’s Bank of China on Thursday, casting another cloud over a potential revival of the share sale.

The meeting would “guide Ant Group to implement financial supervision, fair competition and protect the legitimate rights and interests of consumers,” the statement said.

Ant said it had received a notice from regulators and would “comply with all regulatory requirements”.

Alibaba said it would cooperate with the investigation and that its operations remained normal.

Fred Hu, chairman of Primavera Capital Group, an Ant investor, said global markets would be watching closely to see whether the moves are “politically motivated or genuine impartial law enforcement” and whether regulators target only the private sector but not state monopolies.

“It would be a tragedy if the antitrust law should be seen as ‘targeting’ successful private tech companies only,” he said.

But China political analyst Einar Tangen says foreign firms, in particular, are likely to view Beijing’s anti-monopoly moves positively.

“They’ve been basically foreclosed from the market because of the powerful positions of these [state-owned enterprises] and these homegrown entities like Alibaba and Tencent. Now they will have a free shake at it,” Tangen Said.